CVE-2025-3931
📋 TL;DR
CVE-2025-3931 is an authentication bypass vulnerability in Yggdrasil's DBus component that allows any local system user to dispatch messages to worker processes without proper authorization. This enables attackers to force the package manager worker to install arbitrary RPM packages, leading to local privilege escalation. Systems running vulnerable versions of Yggdrasil with the package manager worker enabled are affected.
💻 Affected Systems
- Yggdrasil
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise via arbitrary package installation leading to root access, data theft, and persistent backdoors.
Likely Case
Local privilege escalation allowing attackers to gain administrative privileges and modify system configurations.
If Mitigated
Limited impact if proper network segmentation and user access controls prevent unauthorized local access.
🎯 Exploit Status
Exploitation requires local user access but is straightforward once access is obtained. The vulnerability is in authentication logic, making exploitation simple.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Version including PR #336 fixes
Vendor Advisory: https://access.redhat.com/errata/RHSA-2025:7592
Restart Required: Yes
Instructions:
1. Update Yggdrasil to version containing PR #336 fixes. 2. Apply Red Hat advisory RHSA-2025:7592 if using Red Hat systems. 3. Restart Yggdrasil service and dependent services.
🔧 Temporary Workarounds
Disable Yggdrasil DBus interface
linuxTemporarily disable the vulnerable DBus interface until patching is possible
systemctl stop yggdrasil
systemctl disable yggdrasil
Restrict DBus access
linuxConfigure DBus policy to restrict access to Yggdrasil methods
Edit /etc/dbus-1/system.d/yggdrasil.conf to add authentication requirements
🧯 If You Can't Patch
- Implement strict user access controls to limit local shell access to trusted users only
- Monitor for suspicious package installation activities and DBus method calls to Yggdrasil
🔍 How to Verify
Check if Vulnerable:
Check Yggdrasil version and verify if PR #336 fixes are applied. Examine DBus configuration for authentication settings.Check Version:
yggdrasil --version or rpm -q yggdrasilVerify Fix Applied:
Verify Yggdrasil version is updated and test that unprivileged users cannot call Yggdrasil DBus methods.📡 Detection & Monitoring
Log Indicators:
- Unauthorized DBus method calls to Yggdrasil
- Unexpected package installations via Yggdrasil worker
- Privilege escalation attempts
Network Indicators:
- Local DBus communication spikes
- Unexpected package repository additions
SIEM Query:
source="yggdrasil" AND (event="dbus_call" OR event="package_install") AND user!="root"